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N14 Problems

Dec 30, 2015 at 12:10 PM CST
+ 3
any advice out there My N14 is nothing but a money pit Replace injectors a
months Ago have to do it again ???
Replied on Wed, Dec 30, 2015 at 12:27 PM CST
+ 1 - 1
Make sure you take a good look at your injectors and the head, when you pull them. It's a three piece head, I would not hesitate to replace one two or all three of the heads.
Replied on Wed, Dec 30, 2015 at 12:29 PM CST
- 1
Daniel, the N14 is notorious for injector issues. When one goes out replace them in pairs. I have two of them, once you get the bugs worked out they are great engines. Heck you can overhaul the whole thing for under $10,000. Throw in some new injectors and you have a new machine again. They just start getting all kinds of flaky things when the get over 1M but so do all of them.
Replied on Wed, Dec 30, 2015 at 03:14 PM CST
Daniel I replaced the injectors in my N14 then 2-3 months later it was screwing up again. Computer said it was injectors.
I cleaned the filter screen in the top of injector pump and the misfire was cured. I love the N14 but I think my ISX is a miserable POS.
Replied on Wed, Dec 30, 2015 at 06:39 PM CST
I have 5 of them. great engines after you figure them out. Injectors are the biggest issue. I've tried all kinds of rebuilders and cummins remans. I would not recommend the cummins remans becouse of cost and had real bad luck with them. The best ones I've found are from interstate-mcbee. I get mine from highwayandheavyparts.com. Real easy people to work with and send a shipping label for cores.

Biggest thing is to make sure you buy clean fuel, clean that little filter on top of pump, I run a fuel filter with a water drain and keep them drained off once a week. We run howes fuel treat and/or some 2 stroke oil in fuel. Injector cups can go bad and allow water in fuel, not .good for injectors. I have a good machine shop that can cut out old one and press in new. Also had trouble with old injector harness, or the drivers in the ecm can go bad and kill an injector. And if you took it to the wrong person to turn up power and got some bad tune. That will really couse trouble.

Get an an extra injector and keep in truck. If your out on the road and one goes out, where ever you go won't have the one you need and they'll burn you on having to order one. There not hard to change done it many times on the side of road.

And like alfred said cheap to rebuild. I saw an add the other day the cummins dealer would inflame an n14 for 8999.00. If they can do it for that I should be able to do it my self for 5k.
Replied on Wed, Dec 30, 2015 at 09:13 PM CST
thanks all u guys for ur advises like to try afew more things
on hope can figure this think out so far kenworth and the local diesel shop '
all they doing racking labor time at 110 per hour it just sucks.
Replied on Thu, Dec 31, 2015 at 08:39 AM CST
There is no way you should have to replace all 6 again. There is another problem. O rings got messed up or were not put on right. There could be a blockage somewhere. Why do you believe they need replaced again
Replied on Thu, Dec 31, 2015 at 02:08 PM CST
Is it missing? I have run a lot of N-14s and worked in a shop where almost all were N-14's about 750 trucks..
My opinion they are easy to work on and easy on the pocket book,,money pit?
Replied on Thu, Dec 31, 2015 at 04:18 PM CST
Quote: "Make sure you take a good look at your injectors and the head, when you pull them. It's a three piece head, I would not hesitate to replace one two or all three of the heads."

Don't use TA fuel with that motor. U will go through injectioners .
Replied on Thu, Dec 31, 2015 at 04:31 PM CST
one thing i had to teach my drivers how to run them cant just get out and keep harming a n-14 when loaded push down on foot pedal till it starts to bog then let up just alittle and let turbo catch up with motor ,u should never have to floor a n-14 to get max power about 2/3 pedal works just find start driving her that way and the computer will acully start letting her breath agin , also when uneed allittle more when using foot pedal insted of cruise turn your cruise button on and this will take it to advertised power 370/435 will kick in the 435 hp/injector are touchie with the junk fuel we have to burn,if you have injector knocking at u uve had your foot in it to hard and have scored plunjer tunnel in injector we use lucus once a wk in winter time usually put in before u idel at night,summertime we do one quart of dextron a wk,but carry ur empty jug with for dot sake,really hot wheather in summer we use ,your going to laugh but we usr 1/2 gallon of crisco cooking oil per fill, on a 100 degree day u will fill a diffreance in foor pedal response with in 10 miles,have 9 n-14 left in fleet ,and after drivers get use to them they will not givem up.
Replied on Fri, Jan 01, 2016 at 07:41 AM CST
we dump a quart of atf in the fuel every other fuel up to help lubricate the injectors
Replied on Fri, Jan 01, 2016 at 12:55 PM CST
Quote: "we dump a quart of atf in the fuel every other fuel up to help lubricate the injectors"

We used to run ATF in the fuel to clean out the fuel system.. BUT. ATF has a red dye in it.. As in if you pour it into your diesel.. It will dye the fuel.. As in showing your fuel as untaxed off road fuel.. Every once in a while the state tax guys will test everybodys fuel, at places like the scales or even along the road.. Looking to see if somebody is running off road fuel.. Red dye from the ATF will show up as off road.. And then the fines begin.. Just something to think about..

Replied on Tue, Jan 05, 2016 at 11:47 AM CST
also another thing I do with mine is run a bottle of power service year round usually every two weeks I have almost 300k on a overhaul and have never had to open it up yet just a thought motor has been in the truck for over a mil
Replied on Tue, Jan 05, 2016 at 12:16 PM CST
You guys would be giving good advice is his injectors were old. He said he just replaced them a couple months ago. No fuel additive ever made could fix fuel bad enough to kill a set of injectors in a couple months time. He's either gettin a shit load of water in his fuel or he's got something else goin on
Replied on Wed, Jan 06, 2016 at 06:33 PM CST
I have an N14 and I took the radiator cap off & found a black sludge overflowing out. Any ideas where to start? Truck runs fine.
Replied on Wed, Jan 06, 2016 at 06:36 PM CST
Quote: "I have an N14 and I took the radiator cap off & found a black sludge overflowing out. Any ideas where to start? Truck runs fine."

I bet your oil cooler has gone bad
Replied on Wed, Jan 06, 2016 at 06:38 PM CST
That's what I thought, hopefully that's all.
Replied on Wed, Jan 06, 2016 at 06:40 PM CST
Thats my guess as well.
Replied on Wed, Jan 06, 2016 at 06:52 PM CST
Thanks guys
Replied on Thu, Jan 07, 2016 at 08:31 AM CST
Quote: "we dump a quart of atf in the fuel every other fuel up to help lubricate the injectors"

I do similar. I have an ISX that went 1.4 million miles before an overhaul. Still had the original injectors in it.

As far as red dye, I haven't had my fuel checked in 20 years. I'll take my chances.
Replied on Thu, Jan 07, 2016 at 09:20 PM CST
well i got the truck out the shop brand new injectors its running good
i use the ATF on the fuel hope that helps
Thanks all u guys for the advice hope things go good for all u folks out there....
Replied on Thu, Jan 07, 2016 at 09:46 PM CST
Did they find a reason why after only a few months it needed new injectors. Atf will get you fined if they dip your tanks. I would check for water or some other contaminants in your fuel tanks. This new fuel is bad but not that bad
Replied on Thu, Jan 07, 2016 at 10:27 PM CST
- 1
Quote: "well i got the truck out the shop brand new injectors its running good i use the ATF on the fuel hope that helps Thanks all u guys for the advice hope things go good for all u folks out there...."

Daniel, I forgot to mention put a couple of bottles of rubbing alcohol in your tanks once a month. This will kill off the algea from the bio fuel, we were having problems with one of our N-14's, I had to take all the fuel lines off and clean them out, there was so much algea in them from this new fuel. I had told the operator that he needed to put in the alcohol at least once a month, he had not done so for three months and then we started having the problems. The N14 does not care for this new fuel, use the alcohol trick once a month, ATF once a month ( which one quart in each tank will disipate the dye does not even show up). You will find your fuel tanks, lines, and injectors will remain clean and lubricated. We have been doing this for quite a while after we noticed the black buildup inside out tanks. Much more cost effective than the other additives, and this one is right in the Volvo owners manual.
Replied on Fri, Jan 08, 2016 at 11:30 AM CST
Quote: "Daniel, I forgot to mention put a couple of bottles of rubbing alcohol in your tanks once a month. This will kill off the algea from the bio fuel, we were having problems with one of our N-14's, I had to take all the fuel lines off and clean them out, there was so much algea in them from this new fuel. I had told the operator that he needed to put in the alcohol at least once a month, he had not done so for three months and then we started having the problems. The N14 does not care for this new fuel, use the alcohol trick once a month, ATF once a month ( which one quart in each tank will disipate the dye does not even show up). You will find your fuel tanks, lines, and injectors will remain clean and lubricated. We have been doing this for quite a while after we noticed the black buildup inside out tanks. Much more cost effective than the other additives, and this one is right in the Volvo owners manual. "

I agree with you Alfred, 1 quart of atf to 100 gallons of diesel does not change the color at all
Replied on Wed, Dec 21, 2016 at 09:31 AM CST
+ 1
Oil cooler is bad. Guaranteed.
Replied on Wed, Dec 21, 2016 at 09:34 AM CST
I mean for the guy with black sludge in his radiator. The oil cooler is bad. Looking at the date he posted, I'm sure he got it fixed by now, but just advice for anyone with the same problem
Replied on Thu, Dec 22, 2016 at 07:34 AM CST
Stay away from Cummins "reman" injectors, heads, ect. Your rolling the dice if you get a good one or not . In efforts to save money their quality control went to s***. I've done that song and dance on a reman complete engine. N14 ISX all the same issues. I bought new injectors for my crate engine now it runs like a top. 3 of 6 weren't right but still passed "computer" cut out test. ISX heads are the same. Reman are 50/50 chance there not cracked . I know this by experience . ...
Replied on Sat, Dec 24, 2016 at 11:02 PM CST
How often do you change fuel filters.
Replied on Sun, Dec 25, 2016 at 11:33 AM CST
Quote: "How often do you change fuel filters."

This time of year (with the winter blend) about once a month, sometimes more depending on the quality of fuel.
Replied on Sun, Dec 25, 2016 at 11:37 AM CST
One of our N-14's is in the shop right now. Replacing two injectors, the seem to last about 300-400 K and then we have to go through them again. That means next year we will replace two more, and then the following year two more. It is the cycle of the N-14, if the dog gone thing did not run so good, I would have gotten rid of it.
Replied on Mon, Dec 26, 2016 at 11:24 AM CST
I guess if I was experiencing premature injector failures I would start looking at fuel lines, they have about a 10 year life span, after that they can start breaking down and send debris to the injectors or just getting a little air in the fuel lines is hell on injectors. As far as adding ATF, I make it in to Walmart now and then to buy gallons of 2 stroke oil. About a quart per 100 gallons I've been adding. Pretty cheap insurance for today's dry fuel and never a chance of looking like died fuel even though I've never heard of ATF turning the color of fuel.
Replied on Mon, Dec 26, 2016 at 01:40 PM CST
Quote: "I guess if I was experiencing premature injector failures I would start looking at fuel lines, they have about a 10 year life span, after that they can start breaking down and send debris to the injectors or just getting a little air in the fuel lines is hell on injectors. As far as adding ATF, I make it in to Walmart now and then to buy gallons of 2 stroke oil. About a quart per 100 gallons I've been adding. Pretty cheap insurance for today's dry fuel and never a chance of looking like died fuel even though I've never heard of ATF turning the color of fuel. "

You are right about the fuel lines. We just replaced those last summer as well as the little filter on the fuel pump. I will give the two stroke oil a try, thanks for the tip.
Replied on Mon, Dec 26, 2016 at 03:14 PM CST
+ 1
I took a little time to think about the 2 stroke oil about 8 years ago, and I've been using it without incident since. My thoughts were that I needed an additive that would lubricate and also was intended to be mixed with fuel and be burnt in an engine. My cat sure likes his "treat" at 870k unmolested miles besides normal overhead adjustments.
Replied on Tue, Dec 27, 2016 at 01:58 PM CST
Quote: "I took a little time to think about the 2 stroke oil about 8 years ago, and I've been using it without incident since. My thoughts were that I needed an additive that would lubricate and also was intended to be mixed with fuel and be burnt in an engine. My cat sure likes his "treat" at 870k unmolested miles besides normal overhead adjustments. "

Good advice.
One of our N14 has 850,000 with no injectors needed. The other has 725,000 with 2 sets installed within the last 150,000. The problem was caused by water in both cases.

The high miler has a Racor filter, the one needed replacements didn't have Racor, but it does now.

I love our N14s but ou4 ICS are a POS.
Replied on Wed, Dec 28, 2016 at 10:57 AM CST
I put a FASS FUEL system on, since then, knock on wood, no injector troubles what so ever. Also use good fuel filters. Fleetgaurd 1000.
Replied on Wed, Dec 28, 2016 at 11:15 AM CST
Correct me if I'm wrong but isn't the fleetguard 1000 just a separator??
Replied on Wed, Dec 28, 2016 at 04:57 PM CST
I Find on my cat engine when adding a quart of 10w30 to my engine oil it makes the injectors run smoother the blowby goes away!
Replied on Wed, Dec 28, 2016 at 08:28 PM CST
+ 1
Last I checked with cummins, it was the recommended fuel filter. And yes I believe it is a water separator. But with my FASS it runs 2 filters, the 1000 and one other, I can't remember the number off top of my head. But when I didn't have FASS, I still ran the 1000 with no issues
Replied on Thu, Dec 29, 2016 at 08:52 AM CST
The best advice gorgeous n-14 problems is to get a cat a 3406 or 6nz should fix you right up
Replied on Thu, Dec 29, 2016 at 09:50 AM CST
That's a good idea, I'll buy your N14 block for 500. He is right total junk make it 300
Replied on Mon, Nov 02, 2020 at 07:17 AM CST
Quote: "I have 5 of them. great engines after you figure them out. Injectors are the biggest issue. I've tried all kinds of rebuilders and cummins remans. I would not recommend the cummins remans becouse of cost and had real bad luck with them. The best ones I've found are from interstate-mcbee. I get mine from highwayandheavyparts.com. Real easy people to work with and send a shipping label for cores. Biggest thing is to make sure you buy clean fuel, clean that little filter on top of pump, I run a fuel filter with a water drain and keep them drained off once a week. We run howes fuel treat and/or some 2 stroke oil in fuel. Injector cups can go bad and allow water in fuel, not .good for injectors. I have a good machine shop that can cut out old one and press in new. Also had trouble with old injector harness, or the drivers in the ecm can go bad and kill an injector. And if you took it to the wrong person to turn up power and got some bad tune. That will really couse trouble. Get an an extra injector and keep in truck. If your out on the road and one goes out, where ever you go won't have the one you need and they'll burn you on having to order one. There not hard to change done it many times on the side of road. And like alfred said cheap to rebuild. I saw an add the other day the cummins dealer would inflame an n14 for 8999.00. If they can do it for that I should be able to do it my self for 5k."

Hey u still running N14s?

Replied on Mon, Nov 02, 2020 at 07:46 AM CST
I had tanks dipped in Montana not long ago at scale

Replied on Mon, Nov 02, 2020 at 08:46 AM CST

Have you replaced your pass thrus in the heads! Check and see if they have oil in the plugs if they do it causes the computer to miss fire the injector.

Replied on Mon, Nov 02, 2020 at 09:03 AM CST
Are you on Facebook? Join the page . Cummins N14 Tech support.
Replied on Tue, Nov 24, 2020 at 07:45 AM CST
Seen that before and was tampered fuel. Fuel tank vandalized with sugar. Clean tanks. I run n14’s for years with no issues.
Replied on Tue, Nov 24, 2020 at 08:48 AM CST
When I had a n14 I added a another fuel Filter (my truck only had 1) after I started having injector problems. I guess it don’t take much more than a spec of sand to wipe a Cummins injector out.🤷🏻‍♂️ I